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Building: Haynes roadster on the Road since november 2014

posted on 11/3/18 at 05:23 PM

Balnking the heating circuit

Hi,
When I built my car, I bypassed the heating circuit ,normally used to heat the inside of the car, with a loop: the water is just circulating in a hose
running around the engine.
But as my engine bay is quite crowded, and I never found, in spite of many tries, the perfect route for the bypass hose, I'm thinking about just
blanking the in and out ports of the heating circuit on the engine, with blanking plugs.
I have a Sierra 2.0i DOHC. the heating circuit runs from the water pump to the thermostat housing.
Will this be a problem? Does the heating circuit need to circulate, or can it be just blanked with no issue on the cooling system?
Thanks in advance for your advices.

It all depends if you have a circuit the coolant can take around the engine before the thermostat opens?
lots of engines the coolant circulates the engine then out around the heater matrix,a fast warm up circuit.

Simple hose from manifold to pump running forward and round front off engine
I put a screw cap T piece in it as it will be highest ppl t of the system for bleeding.
The head can get hot spots if the out let is blocked

I eat to survive
I drink to forget
I breath to wee my ex wife off (and now my ex partner)

quote:Originally posted by snapper
Simple hose from manifold to pump running forward and round front off engine
I put a screw cap T piece in it as it will be highest ppl t of the system for bleeding.
The head can get hot spots if the out let is blocked

Everything above ^, can't imagine your engine bay is so crowded one small hose is a problem tbh, maybe it needs a review of the layout and a
tidy up

Photo Archive
Building: Haynes roadster on the Road since november 2014

posted on 12/3/18 at 09:48 AM

Thank you very much for your answers.

OK, I understand your points, and I won't block the heating circuit off, and keep the bypass.

As I said in my first post, I already have a bypass hose which is quite tidy I think: it is a piece of Formline hose connected to the engine with 2
silicone elbows, as the in and out ports of the heating circuit are on opposite sides of the engine, and both pointing outward!

The reason I wanted to remove the bypass is that I'm not happy with how it is set-up now, and I couldn't find a better way to route it.

The problem is on the intake side of my engine bay, which is very crowded, and what ever the route I try, this hose is always close to interfere with
something: intake manifold that had to be shorten to fit under the bonnet, the other water hoses, the thermostat housing, the sensors (water temp, fan
switch), the hose to the ISCV, the alternator, the belt to the crack pulley, or even the electric engine loom, etc.

Not sure it the thermostat housing is the same as on a 2000 blacktop but in my tiger I have the heater and bypass ports blanked off. For a bypass you
then drill a hole through the top of the thermostat (i drilled 3). This then allows water to circulate. This is what tiger do/recommended

quote:Originally posted by furryeggs
Not sure it the thermostat housing is the same as on a 2000 blacktop but in my tiger I have the heater and bypass ports blanked off. For a bypass you
then drill a hole through the top of the thermostat (i drilled 3). This then allows water to circulate. This is what tiger do/recommended

The Toyota engine in my car had three "bypasses". One through the heater, one through an Oil/Water cooler and a third one which was only
open when cold. As the thermostat opened the main cooling circuit it closed that one.
I duly blocked them all off and drilled several holes in the stat.
When the engine was cold you could see the top hose "pumping up" when the engine was revved. Once the stat was open the effect was less
but still there.
Long story short, it blew off.
I have since fitted a remote stat with a proper bypass. As part of my current new engine build I plan to re-instate the oil/water cooler too.

quote:Originally posted by CosKev3
It all depends if you have a circuit the coolant can take around the engine before the thermostat opens?
lots of engines the coolant circulates the engine then out around the heater matrix,a fast warm up circuit.

[Edited on 11/3/18 by CosKev3]

^^^^
This is all that matters!

1. Easiest check to get an idea of whether its safe is the original cars heating system / matrix. Many years ago they started to include a flow valve
stopping water flow normally positioned in the main temperature unit within the cabin (its to stop heatsoak into the cabin when set to off), which
meant only residual heat would pass into the pipes with no water flow. If this is in place it is controlled by the heating system controls and nothing
to do with the engine which meant the engine would be fine with no water flow down these pipes. Meaning it has its own by pass pipes.

If the above is true blocking them off will cause no issues as the water not moving in that small bit of pipe would be the same as the heater valve
closed at the other end of the pipe.

Heating systems are an add on for comfort for passenger not for the health / performance of an engine, the only difference for us is some of our
engines are older so have to be checked. I had a modified Toyota supra at 450BHP when the heater matrix went I called the Tuners and they said
blocking it up until I replaced the heater matrix was fine as the engines are designed to run at temperature with the minimum cooling occurring or
they'd overheat when all cooling areas weren't turned on.

I'm actually looking into blocking mine up at the moment to ditch the weight of the pipes extra coolant and heavy heating aircon unit, probably
drop a good 20kg overall I think